Kabuto was portrayed as being really skilled in the first series but he hasn't done much in Shippuuden. He's an expert psycho medic and his body is getting overtaken by Orochimaru, my favorite character.

Anko was Orochimaru's first apprentice and she was strong enough to survive the curse seal process. She was trained by Orochimaru and knows some forbidden techniques and she fights with snakes.

This fight would be excellent imo. Orochimaru's body vomiting is always cool to see and in this fight you've got two people who could be doing that all over the place. Both of them might be vomiting up scrolls and weapons as well. There'd be snakes flying all over the place and all types of disturbing stuff. On top of that, Anko has a curse seal so maybe she can grow wings or at least transform like Orochimaru's crew could.